Value share-like capital by asset type for the sale-expense deduction

.github/test_outcome_allowlist.toml

@@ -64,3 +64,10 @@ nodeid = "policyengine_uk/tests/test_dwp_published_rates.py::test_projection_con
 outcome = "skipped"
 reason = '^(not uprated|series ends before 2026-27|Universal Credit Act 2025 s\.1 departs from CPI uprating)$'
 why = "The test is parametrised over every DWP rate parameter and skips those it does not apply to: parameters with no uprating, series that end before 2026-27, and the four UC standard allowances, whose minimum the Universal Credit Act 2025 s.1 sets above CPI uprating (#1925). The LCWRA element, frozen by s.3, is checked against its own uprating index (#2284). 64 cases on 12 October 2026."
+
+[[allow]]
+nodeid = "policyengine_uk/tests/microsimulation/test_annual_allowance_against_hmrc.py::test_2024_annual_allowance_charge_and_payers_are_near_hmrc"
+outcome = "xfailed"
+reason = "policyengine-uk-data#606"
+data = ["present"]
+why = "Known data gaps, chiefly PolicyEngine/policyengine-uk-data#606: the certified Enhanced FRS imputes employer pension contributions as three times employee contributions, which puts the 2024 annual allowance count, charge and excess several times above HMRC's; with a third of those contributions all three fall within the band. Pinned by a strict xfail until the data is fixed (#2523)."

.github/workflows/aggregate-impact.yaml

@@ -1,6 +1,8 @@
 # Measure a pull request's base and head on the certified dataset and post
 # the comparison: receipts by tax head, spending and caseloads, poverty,
 # inequality, deciles and the standard reform costings, 2025-26 to 2031-32.
+# For a pull request, the head is GitHub's merge commit and the base is that
+# commit's first parent, so the report is exactly what merging would change.
 #
 # Both sides run the pull request head's copy of the measurement tool
 # (policyengine_uk/utils/aggregate_impact), each in an environment synced
@@ -66,16 +68,15 @@ jobs:
         id: commits
         env:
           EVENT: ${{ github.event_name }}
-          PR_BASE: ${{ github.event.pull_request.base.sha }}
           PR_BASE_REF: ${{ github.event.pull_request.base.ref }}
           PR_NUMBER: ${{ github.event.pull_request.number }}
           INPUT_BASE: ${{ inputs.base }}
           INPUT_HEAD: ${{ inputs.head }}
         run: |
-          # A pull request's head is its merge commit, whose first parent is
-          # the base, so the comparison is exactly what merging would change.
+          # A pull request's head is its merge commit. Its base is read from
+          # that commit once the head is checked out (Choose the base).
           if [ "$EVENT" = "pull_request" ]; then
-            base="$PR_BASE"; head="$GITHUB_SHA"
+            base=""; head="$GITHUB_SHA"
             base_name="$PR_BASE_REF"; head_name="#$PR_NUMBER merged into $PR_BASE_REF"
           else
             base="${INPUT_BASE:-main}"; head="${INPUT_HEAD:-$GITHUB_SHA}"
@@ -93,11 +94,39 @@ jobs:
         with:
           ref: ${{ steps.commits.outputs.head }}
           path: head
+          # A pull request's merge commit and its parents, so that the next
+          # step can read the base from it.
+          fetch-depth: 2
+
+      - name: Choose the base
+        id: base
+        env:
+          EVENT: ${{ github.event_name }}
+          BASE: ${{ steps.commits.outputs.base }}
+        run: |
+          # A pull request's base is its merge commit's first parent: the tip
+          # of the branch it merges into, as GitHub made the merge commit for
+          # this run. The comparison is then exactly what merging would
+          # change. The event's pull_request.base.sha is not that commit: it
+          # lags the branch once the branch has moved on, and the report then
+          # counted the branch's newer merges as the pull request's impact
+          # (#2516's took in 26 commits from main).
+          if [ "$EVENT" = "pull_request" ]; then
+            # The merge commit, then its parents.
+            line=$(git -C head rev-list --parents -n 1 HEAD)
+            read -r -a commit <<< "$line"
+            if [ "${#commit[@]}" -ne 3 ]; then
+              echo "::error::The head ${commit[0]} has $((${#commit[@]} - 1)) parents, not 2, so it is not a pull request's merge commit and its base is unknown."
+              exit 1
+            fi
+            BASE="${commit[1]}"
+          fi
+          echo "sha=$BASE" >> "$GITHUB_OUTPUT"
 
       - name: Check out the base
         uses: actions/checkout@v6
         with:
-          ref: ${{ steps.commits.outputs.base }}
+          ref: ${{ steps.base.outputs.sha }}
           path: base
 
       - name: Install uv

.github/workflows/pr_code_changes.yaml

@@ -162,7 +162,7 @@ jobs:
         run: uv pip install policyengine --system
       - name: Test documentation builds
         run: make documentation
-  # The YAML tests, the Python tests on four runners, and the check that
+  # The YAML tests, the Python tests on five runners, and the check that
   # every test ran once and passed, in the locked environment. As one job
   # they took 59 minutes on 10 October 2026 (run 38075384588), and runs were
   # cancelled at a 60-minute limit (issues #2099 and #2257). The release

.github/workflows/test-suite.yaml

@@ -4,10 +4,10 @@
 # publish. All three run the same jobs in the same locked environment.
 #
 # Jobs: the YAML policy tests (which also list every Python test), the Python
-# tests split over four runners, and Result, which fails unless every listed
+# tests split over five runners, and Result, which fails unless every listed
 # Python test ran in exactly one shard and passed, apart from the outcomes
 # accepted in .github/test_outcome_allowlist.toml. A caller that names its job
-# Test gets the checks "Test / YAML", "Test / Python K/4" and "Test / Result";
+# Test gets the checks "Test / YAML", "Test / Python K/5" and "Test / Result";
 # "Test / Result" is the one to require.
 
 name: Test suite
@@ -82,6 +82,9 @@ jobs:
           TESTS: ${{ steps.env.outputs.tests }}
         run: policyengine-core test "$TESTS/policy" -c policyengine_uk
       - name: List the Python tests
+        id: collect
+        # Keep Result's coverage audit available after a policy YAML failure.
+        if: ${{ !cancelled() && steps.env.outcome == 'success' }}
         # Every Python test, collected without --shard, in the environment
         # the shards use. Result checks that the shards ran each of these
         # exactly once.
@@ -99,6 +102,7 @@ jobs:
             --collect-only -q -p no:cacheprovider > collected.txt
           tail -n 1 collected.txt
       - name: Upload the list of Python tests
+        if: ${{ !cancelled() && steps.collect.outcome == 'success' }}
         uses: actions/upload-artifact@v7
         with:
           name: test-collected
@@ -118,17 +122,23 @@ jobs:
     # the 16 GB runners peaked at 15.6 GB, 283 MB short of running out
     # (run 38156967136; two shards of an earlier run lost their runners).
     # With four, each worker runs about a quarter fewer tests.
+    #
+    # Five, not four, for time: on 20 and 21 October shard 1/4 took 50 to
+    # 52 minutes on unrelated pull requests, close to the timeout. A pull
+    # request adding about a fifth more parameters (#1855) hit the timeout
+    # on shard 1/4 twice, and its other shards took 48 to 59 minutes (run
+    # 39568525017).
     name: Python ${{ matrix.shard }}/${{ strategy.job-total }}
     if: ${{ !inputs.skip }}
     runs-on: ubuntu-24.04-arm
     # The shards took 15, 20 and 15 minutes on 10 October (run
-    # 38085920460). 60 minutes leaves room for a slow runner and still
-    # stops a hung shard.
+    # 38085920460), and up to 52 minutes with four shards on 21 October.
+    # 60 minutes leaves room for a slow runner and still stops a hung shard.
     timeout-minutes: 60
     strategy:
       fail-fast: false
       matrix:
-        shard: [1, 2, 3, 4]
+        shard: [1, 2, 3, 4, 5]
     steps:
       - name: Checkout repo
         uses: actions/checkout@v6